Underwater platform



FIG. 1 is a front, top, right side perspective view of an underwater platform showing my new design;

FIG. 2 is a right side elevational view thereof, the left side being identical thereto;

FIG. 3 is a front elevational view thereof, the rear being identical thereto; and,

FIG. 4 is a top plan view thereof, the bottom being identical thereto. 

The ornamental design of an underwater platform, as shown and described. 